This invention relates to propulsion vehicles in general and more particularly to a method for determining spinning or slipping of wheels in propulsion vehicles without dead axles.
In rail vehicles, rotation of the wheels without frictionally secured rolling is to be avoided. In starting, this type of rotation is called spinning and, in braking, slipping. Spinning and slipping of the wheels can come about if the individual drive or braking steps are selected in too rapid a sequence, if the friction coefficient between the wheel and its support is reduced due to fallen leaves, moisture or ice formation on the track surface, or, in the case of bogie locomotives, if the phenomenon of axle pressure displacement occurs. It is desirable to indicate spinning or slipping by means of a signaling device and to utilize it, preferably in an automatic control, for correcting the drive power.
For determining spinning or slipping of the drive wheels of railroad vehicles it is known to attach a tachometer generator to each dead or driving axle and to connect the voltages of the tachometer generators, in series bucking, to the coil of a relay. In the case of spinning or slipping, a difference between the speeds of the dead axle and the driving axle appears. The voltage difference between the bucking tachometer generators energizes the relay, the contacts of which interrupt the circuit of the drive motor.
However, devices of this known type are basically not suitable for many modern rail vehicles such as long distance and local railroads, trolley cars and self-propelled Diesel cars, if such vehicles have exclusively driving axles or driving axles, plus mechanically braked axles, but no plain dead axles. The actual vehicle velocity can be determined reliably only on a plain dead axle.
From the German Pat. No. 11 78 899, a method for determining spinning or slipping of drive wheels in rail vehicles without dead axles is known, in which the acceleration of the driven wheels as well as the acceleration of the vehicle is determined. Differences between the accelerations of the drive wheel and the vehicle are evaluated as spinning or slipping signals. In this known method, it is a disadvantage that both a measuring transducer for the wheel acceleration and a measuring transducer for the linear acceleration of the vehicle are necessary. While the measuring transducer for the drive wheel acceleration can simply consist of a tachometer generator driven by the drive wheel, having its output conducted through a differentiating member, a linear accelerometer working according to the inertia principle and which contains an elaborate seismic system, is necessary as the acceleration transducer for the vehicle velocity.